1. Field of the Invention
The invention relates to the field of fire hydrants and, more particularly, to a dry (unpressurized) hydrant which minimizes the possibility of clogging of the hydrant intake and which is suitable for use with bodies of water having variable water levels.
2. Description of the Prior Art
Dry hydrants are a type of fire service hydrant for use where there is no source of pressurized water. For example, in rural areas where there is no centralized water service, water for firefighting is commonly drawn from lakes, ponds, cisterns or the like. Typically, a tanker truck will draw water from a nearby body of water using a flexible hose fitted with a strainer to prevent debris from being drawn into the hose. The tanker will then travel to the site of the fire, where a pumper truck draws water from the tanker to fight the fire.
Such an arrangement is inconvenient and may waste valuable time while the special strainer is being connected to the hose. The strainer assembly must then be properly disposed within the body of water. If placed indiscriminately, the strainer may draw debris, leaves or mud which will clog the strainer and diminish the flow of water to the tanker.
One recent solution to these problems has been to install a so-called "dry-hydrant". A dry hydrant is a length of pipe having one end disposed below the water line of a body of water and the other end exposed at or near the shoreline. Such an arrangement is shown in application Ser. Nos. 07/702,202 and 07/702,203, filed May 17, 1991.
In these arrangements, a length of polyvinylchloride (PVC) pipe is laid in a trench dug from the shoreline of a body of water to enable one end of the pipe to be disposed at a predetermined fixed depth in the water. The other end of the pipe is connected via a 90.degree. elbow to a vertical standpipe. The standpipe is provided with a coupling which enables a standard fire service hose to be connected to the standpipe to draw water through the dry hydrant to a tanker truck.
The portion of the intake pipe disposed in the body of water may be provided with a strainer to prevent debris from being drawn through the dry hydrant and into the tanker.
One drawback to a fixed dry hydrant installation, as described above, is where the body of water is brackish or contains salt water, or contains a lot of marine growth. Barnacles, seaweed, algae, or other marine growth can rapidly cover the intake and strainer of fixed hydrant intake pipe. One solution would be to periodically clean the intake pipe. However, this is a costly solution because of the additional cost of cleaning.
A second drawback to the fixed dry hydrant arrangement is that during times of drought or low water levels in the body of water, the water level may drop below the end of the intake pipe, rendering the dry hydrant ineffective.
It would therefore be beneficial to have available a dry hydrant which is low in cost and easy and inexpensive to install which is less susceptible to the effects of marine growth and where the depth of the intake pipe may be adjusted to ensure a consistent flow of water when needed.